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Abstract Detail

Anatomy and Morphology

Olszewski, Magdalena [1], Adel El Miari, Hiba [2], Behdarvandi, Behrang [3], Costea, Mihai [1].

Diversity and evolution of seeds in Cuscuta (dodders, Convolvulaceae): morphology and structure.

Cuscuta is a genus of nearly 200 obligate stem parasites with subcosmopolitan distribution and considerable agricultural and ecological significance. Dodder seeds are considered unspecialized, with no morphological adaptations towards particular dispersal vectors; however, the seed coat anatomy has recently suggested structural features that enable endozoochory. Historically, dodder seeds attracted attention mostly for identification purposes but these few studies were limited to a reduced number of species and had only a regional nature. This is the first attempt to provide a genus-wide overview of the seed diversity in Cuscuta together with an assessment of the usefulness of seed characters for the systematics of the genus. We conducted a preliminary morphometric study using two closely related and difficult to separate North American species of sect. Oxycarpae, C. gronovii and C. umbrosa, which indicated that in most cases seed features can be used to distinguish species. Subsequently, we surveyed the seed morphology and anatomy of 140 species belonging to all the four Cuscuta subgenera. Species of the first infrageneric dodder lineage diverged, subg. Monogynella, have the seed coat cells elongated and puzzle-like, morphologically uninfluenced by dryness/wetness. In contrast, seeds of the other subgenera, Cuscuta, Pachystigma and Grammica are more or less isodiametric and have evolved the ability to alternate their morphology and physiology between two states: with deeply pitted epidermal surface when dry, and papillose through hydration. Seeds with a globose radicular end, likely having a storage function, have evolved only in sect. Denticulatae. Other characters, such as the seed size, hilar region morphology, seed coat micromorphology, the number of palisade layers and their size can be used to distinguish species within various clades of subg. Grammica.

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Related Links:
Digital Atlas of Cuscuta

1 - Wilfrid Laurier University, Biology, 75 University Ave W, Waterloo, ON, N2L3C5, CAN
2 - Wilfrid Laurier University, 75 University Ave W, Waterloo, ON, N2L3C5, Canada
3 - University of Guelph, 50 Stone Road East , Guelph, ON, N1G 2W1, CAN

character evolution

Presentation Type: Poster
Session: P, Anatomy and Morphology
Location: Grand Ballroom - Exhibit Hall/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 5:30 PM This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PAM008
Abstract ID:392
Candidate for Awards:Developmental and Structural Section best poster,Ian and Syvia Taylor Award

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